*{
  margin:0;
  padding: 0;
  list-style: none;
}
html,body{
  width: 100%;
  height: 100%;
}
.app{
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction: column;
}
.body{
  display: flex;
  .left{
    width: 200px;
    height: 100%;
  }
  .right{
    width: 100%;
    height: 100%;
  }
  .active{
    color: red;
  }
}